How do you prepare a standard solution for volumetric analysis?

To prepare a standard solution for volumetric analysis, you make a solution that contains an exact known concentration of a substance (called the primary standard).

Here are the steps to prepare it:

1. Choose a suitable solute:
   Select a pure, stable, and non-hygroscopic substance that can be accurately weighed (for example, sodium carbonate, oxalic acid, or potassium hydrogen phthalate).
2. Weigh the solute accurately:
   Use an analytical balance to weigh the required amount of the solute.
3. Dissolve the solute:
   Transfer the solute into a clean beaker and dissolve it in a small amount of distilled water. Stir until it completely dissolves.
4. Transfer to a volumetric flask:
   Pour the solution carefully into a volumetric flask (of known volume, e.g., 250 mL or 1 L). Use a funnel if needed.
5. Rinse the beaker and funnel:
   Wash the beaker and funnel with distilled water and pour the washings into the flask to ensure all solute is transferred.
6. Make up to the mark:
   Add distilled water up to the calibration mark on the neck of the flask. Use a dropper for the final few drops to be precise.
7. Mix thoroughly:
   Stopper the flask and invert it several times to ensure the solution is uniform.

The solution is now ready and its concentration is known accurately — this is your standard solution used for titration or other volumetric analysis.